nordic spim: does not work with SPI-SDHC infrastructure

[pabigot]

As summarized in #27841 (comment) samples/subsys/fs/fat_fs/ does not run correctly when controlled by a SPI3 configured as nordic,nrf-spim. It appears that CSn is not being correctly deasserted at the end of transactions. this is true, but is probably a secondary effect of the sdhc disk access layer not being consistent about checking return codes

[pabigot]

This is because SPIM can't transmit data from flash, so an initial transfer of 74 clocks to synchronize is never sent.

[pabigot]

Because SPI transfers from data buffers stored in flash fail, and because the disk_access_spi_sdhc layer doesn't check error codes, large numbers of critical SPI transfers are not being transmitted, so the driver never detects that the device is actually present and able to respond.